Program Director: Apodaca, Gerard L. Project Narrative. The umbrella cells that line the inner surface of the bladder must adjust their membrane area as the bladder fills and empties. Increases in area are mediated by insertion (exocytosis) of a pool of small vesicles that underlie the cell surface, while decreases in area are accomplished by internalizing the added membrane through a process called endocytosis. Understanding exocytosis and endocytosis is important because bacteria use these processes to enter and exit bladder cells and defects in exocytosis/endocytosis may account for the altered cell surface expression of proteins that is observed in diseases like interstitial cystitis. Program Director: Apodaca, Gerard L. Facilities: Laboratory: This project will be performed in the Renal-Electrolyte Division Laboratories, located on the 9"^ floor of Scaife Hall. Dr. Apodaca's Scaife laboratory includes 600 square feet of space that is devoted to bladder research, and an adjoining 400 square foot laboratory for work with MDCK cells. Additional facilities include a 100 square foot room that houses our TEM, a 100 square foot room that houses our SEM, a 200 square foot cell culture facility, a 400 square foot microscopy room located across the hall, and adjacent equipment rooms. Clinical: N/A Animal: Housing for small and large mammals is provided on the 10th floor of the newly renovated Animal Care facility located in the South Biomedical Science Tower, adjacent to Scaife Hall. Computer: The Apodaca laboratory is equipped with several PowerPC Macintoshes (G4 and G5), an HP 4000 series laser printer, a Tektronix 840 color laser printer, a Kodak dye sublimation printer, an Agfa Arcus II desktop scanner, and several word processing, graphics, and image analysis software packages including Volocity. The laboratory also houses an Apple Bioinformatics Server with a 2 terabyte RAID storage device. Office: Dr. Apodaca's office is adjacent to the laboratory and is 200 square feet in area. Other: Machine and electronic shops are located in the basement of Scaife Hall. Their services include design, fabrication, and repair of equipment. The University of Pittsburgh Transgenic and Gene Targeting Facility and the Proteomics Facility are located in the adjacent Bioscience Towers of the School of Medicine.